The present invention relates to an audio signal processing apparatus and an audio apparatus. In particular, the present invention relates to an audio signal processing apparatus and an audio apparatus for supplying a multi-channel audio signal.
Conventionally, an amplifier apparatus, connected to a reproduction apparatus serving as an audio signal source, for performing a process such as amplification to an audio signal supplied from the reproduction apparatus side, and for supplying the processed audio signal to a loudspeaker apparatus connected to the amplifier apparatus to output a sound, an apparatus called an AV amplifier apparatus (abbreviation of an audio visual center amplifier apparatus) is known. The AV amplifier apparatus is a multi-functional audio device for performing an advanced process of audio signals synchronized with video images (audio signals which are not related to the video images may be input), and is designed such that a sound field, sound quality, and the like can be set in arbitrary states.
In this AV amplifier apparatus, as audio signals to be input, in addition to an ordinary two-channel stereo audio signal, audio signals, called multi-channel audio signals, of five channels may be input. For example, audio signals of total of six channels, i.e., a front left channel, a front right channel, a center channel, a rear left channel, and a rear right channel, and a low-band dedicated channel may be input. In such a channel configuration, the low-band dedicated channel is regarded as 0.1 channel, and this channel and the five channels may be called 5.1 channels. The signal of the low-band dedicated channel is an audio signal whose band is lower than, e.g., about 120 Hz, and the signal is supplied and output to a loudspeaker apparatus, called a super woofer, for reproducing a low-band sound. When the super woofer is not used, the signal is mixed to the signals of the other channels, the signal of the low-band dedicated channel is reproduced from loudspeaker apparatuses for the other channels together with the other channels. The channels other than the low-band dedicated channel are supplied to the loudspeaker apparatuses arranged at respective positions in a room as respective channels, for example, a plurality of loudspeaker apparatuses are arranged around a listener, so that a stereophonic space is formed.
Such an AV amplifier apparatus comprises, in addition to terminals for connecting a plurality of loudspeaker apparatuses, a terminal for connecting a headphone apparatus. As described above, audio signals may be output from the plurality of loudspeaker apparatuses, and audio signal can also be output from the headphone apparatuses.
The audio signals output from the headphone terminal of the AV amplifier apparatus described above are signals of two channels, i.e., a front left channel and a front right channel. For example, the audio signals of the two channels are supplied to the AV amplifier apparatus, and a sound based on the audio signals of two front left and right channels is output from at least one pair of loudspeaker apparatuses, connected to the AV amplifier apparatus, for the front left and right channels. In this setting, a sound output from the headphone apparatus connected to the headphone terminal of the AV amplifier apparatus is basically set in the same state as that of the sound output from the loudspeaker apparatuses described above.
However, in a state in which five-channel, i.e., multi-channel audio signals are input to an AV amplifier apparatus, in a setting in which a sound based on the supplied multi-channel audio signals is output from the multi-channel loudspeaker apparatuses, connected to the AV amplifier apparatus, for the respective channels, a sound output from the headphone apparatus connected to the headphone terminal of the AV amplifier apparatus is constituted by only the sounds of the two front channels of the sounds of the five channels constituting the multi-channel audio. As a result, a user using the headphone apparatus listens to only the sounds of some channels of, e.g., the five channels.
More specifically, when the multi-channel audio signals of 5.1 channels described above is input to the AV amplifier apparatus as audio signals of a movie, voice of speech (words) synchronized with moving pictures of the movie is mainly included in the center channel, and only a sound such as music is output from the left and right loudspeaker apparatuses by the signals of the two front left and right channels. In this case, only a sound (music in the above example) included in the two front left and right channels is output from the headphone apparatus connected to the AV amplifier apparatus, words of the movie included in the center channel cannot be heard. The user cannot hear various sound effects or the like included in the rear channels of the 5.1 channels by means of the headphone apparatus.
In order to solve this problem, for example, when the headphone apparatus is connected, a setting is preferably made such that the process of converting multi-channel audio into two-channel audio in the AV amplifier apparatus is performed. However, in this setting, a sound output from the stationary loudspeaker apparatus connected to the AV amplifier apparatus is also of two-channel audio obtained by converting the multi-channel audio.
Therefore, when appropriate multi-channel audio is heard by using a headphone apparatus in a conventional AV amplifier apparatus, not only switching of a switch for turning off the stationary loudspeakers is simply performed, an operation for setting the processing state of multi-channel audio by a mode setting must be performed. When the state in which the headphone apparatus is used is returned to the state in which the stationary loudspeaker apparatus are used, an operation of returning the state to the original setting state must be performed. A problem that the operation is very complex is posed.
It is an object of the present invention to make it possible that an outputting operation of multi-channel audio signals from a loudspeaker apparatus and an outputting operation of the signals from a headphone apparatus are preferably performed.
In the first invention, an audio signal processing apparatus comprises, an input unit to which at least an audio signal of a left channel, an audio signal of a right channel, and an audio signal of a center channel are supplied, a first output terminal unit for outputting the audio signal of the left channel, the audio signal of the right channel, and the audio signal of the center channel which are supplied to the input unit, a mixing unit for mixing the audio signal of the center channel to the audio signal of the left channel and mixing the audio signal of the center channel to the audio signal of the right channel to output the mixed signals as audio signals of two channels, and a second output terminal unit for outputting the audio signals of the two channels from the mixing unit. In this manner, the audio signal of the left channel, the audio signal of the right channel, and the audio signal of the center channel are independently output from the output terminal unit, and the audio signals of the two channels obtained by mixing a signal component of the center channel to the audio signal of the left channel and the audio signal of the right channel are output from the second output terminal unit, so that the audio signals of two different types of channel forms can be output from one audio signal processing apparatus. For example, the first output terminal unit is connected to a stationary loudspeaker apparatus, and the second output terminal unit is connected to a headphone apparatus, so that an outputting operation of an audio signal of a channel form being appropriate to the stationary loudspeaker apparatus and an outputting operation of an audio signal of a channel form being appropriate to the headphone apparatus can be properly performed by selection of the output terminal units.
In the second invention, in the audio signal processing apparatus according to the first invention, the audio signal processing apparatus further comprises a switching unit for selectively supplying the audio signal of the left channel and the audio signal of the right channel supplied to the second output terminal unit through the input unit and the audio signals of the two channels from the mixing unit. In this manner, a switching operation between the state in which the outputting operation of the audio signal which is mixed with the audio signal of the center channel is performed, and the state in which the outputting operation of the audio signal which is not mixed with the audio signal of the center channel can be easily performed by operating the switching unit.
In the third invention, in the audio signal processing apparatus according to the second invention, the switching unit selectively supplies the audio signal of the left channel and the audio signal of the right channel supplied to the first output terminal unit through the input unit and the audio signals of the two channels from the mixing unit. In this manner, the audio signal of the left channel and the audio signal of the right channel supplied to the first output terminal unit can be easily output from the second output terminal unit by a switching operation of the switching unit.
In the fourth invention, an audio apparatus comprises an input unit to which at least an audio signal of a left channel, an audio signal of a right channel, and an audio signal of a center channel are supplied, a first output terminal unit, to which a plurality of loudspeaker apparatuses are connected, for outputting at least the audio signal of the left channel and the audio signal of the right channel of the audio signal of the left channel, the audio signal of the right channel, and the audio signal of the center channel supplied to the input unit, a mixing unit for mixing the audio signal of the center channel to the audio signal of the left channel and mixing the audio signal of the center channel to the audio signal of the right channel to output the mixed signals as audio signals of two channels, and a second output terminal unit to which the audio signals of the two channels from the mixing unit and to which a headphone apparatus is connected. In this manner, the audio signal of the left channel, the audio signal of the right channel, and the audio signal of the center channel are independently supplied to a plurality of loudspeaker apparatuses connected to the first output units, and the audio signals of the respective channels are independently output from the loudspeaker apparatuses. The signals obtained by mixing the audio signal of the center channel to the audio signal of the left channel and the audio signal of the right channel are supplied to the headphone apparatus connected to the second output terminal unit, and the audio signals including the center channel are output from the headphone apparatus.
In the fifth invention, in the audio apparatus according to the fourth invention, the audio apparatus further comprises a switching unit for selectively supplying the audio signal of the left channel and the audio signal of the right channel supplied to the second output terminal unit through the input unit and the audio signals of the two channels from the mixing unit. In this manner, a switching operation between the state in which the outputting operation of the audio signal which is mixed with the audio signal of the center channel from the headphone apparatus connected to the second output terminal unit is performed, and the state in which the outputting operation of the audio signal which is not mixed with the audio signal of the center channel can be easily performed by operating the switching unit.
In the sixth invention, in the audio apparatus according to the fifth invention, the switching unit selectively supplies the audio signal of the left channel and the audio signal of the right channel supplied to the first output terminal unit through the input unit and the audio signals of the two channels from the mixing unit. In this manner, the audio signal of the left channel and the audio signal of the right channel supplied from the first output terminal unit to the loudspeaker apparatuses can be easily output from the second output terminal unit to the headphone apparatus by a switching operation of the switching unit.
In the seventh invention, in the audio apparatus according to the fourth invention, the first output terminal unit comprises a first output unit for outputting at least the audio signal of the left channel and the audio signal of the right channel of the audio signal of the left channel and the audio signal of the right channel supplied to the input unit and the audio signal of the center channel, and a second output unit for respectively outputting the audio signal of the left channel, the audio signal of the right channel, and the audio signal of the center channel supplied to the input unit. In this manner, loudspeaker apparatuses can be independently connected to the first output unit and the second output unit, and a channel configuration of the loudspeaker apparatuses respectively connected to the output unit can be changed.
In the eighth invention, in the audio apparatus according to the seventh invention, the apparatus further comprises a switching unit for selectively supplying at least the audio signal of the left channel and the audio signal of the right channel of the audio signal of the left channel and the audio signal of the right channel supplied to the input unit and the audio signal of the center channel to at least one output unit of the first output unit and the second output unit. In this manner, outputting operations of at least the audio signal of the left channel and the audio signal of the right channel can be easily selected by operating the switching unit.